Answer to Question #262051 in Mechanics | Relativity for lowrayne

Question

Car A of mass of 2000 kg moving at 72 km/h. east try to overtake car B of mass

1250 kg moving at 60 km/h, east. Car A collides with car B. The car stick

together after the collision. Find their velocity after collision. (It should be in

m/s).

Answer 1

$m_1v_1+m_2v_2=u(m_1+m_2),$ $\implies$

$u=\frac{m_1v_1+m_2v_2}{m_1+m_2}=67.4~\frac{km}h=18.7~\frac ms.$